Acoustic echoes exist in almost all voice communication devices. A far end speech signal is sent to a loud speaker at a near end to be played back, and inevitably, a near end microphone will pick up, more or less, the played back speech signals, i.e., acoustic echoes. Without removing these acoustic echoes, a far end user will hear her/his own voice, making efficient communication difficult. Acoustic echo cancellation (AEC) can attenuate or remove these acoustic echoes before the near end microphone signal is sent to the far end.